Method of making sterile containers



Dec. 11, 1956 T E, plAzzE ETAL 2,773,285

METHOD OF MAKING STERILE CONTAINERS Filed Nov. 6. 1947 Nil/NT@ Il Hll'llllllll |||rl1l| I EL United States Patent O METHOD OF MAKING STERILECONTAINERS Thomas E. Piazze and Thomas R. Baxter, Mount Vernon, Ohio,assignors, by mesne assignments, to Continental Can Company, Inc., NewYork, N. Y., a corporation of New York Application November 6, 1947,Serial N o. 784,430

2 Claims. (Cl. 18-47.5)

This invention is concerned with improvements in containers and methodsof making the same, and relates more 11. The containers are adapted tobe detached, one

particularly to a series of integrally connected flexible containerswhich `are initially provided in hermetically sealed, sterile conditionand which are adapted to remain in such condition until they are severedto provide individual containers for use.

Serial No. 668,267, Nursing Bottle Top, tiled May 8, 1946, nowabandoned, and Serial No. 743,112, Closure Device for Containers, filedApril 22, 1947, now Patent No. 2,520,335, containers are shown which aremade of transparent flexible material and which are used as disposablenursing bottles. In supplying containers for this purpose it is very`desirable to provide containers which may be furnished to the ultimateuser in closed and sterile condition and which may be easily maintain-edin such condition until it is desired to attach the individualcontainers to the tops orholders for use.

,It is an object of this invention to provide a plurality of containersin the form of a continuous tube having the inner walls sterilized andhaving spaced transverse sealing areas whereby individual containers maybe severed from the tubeas they are desired for use and the remainingcontainers will be maintained in sealed and sterilized condition.

It is a further object of the invention to form sterilized containers byproviding a tube of transparent material and transversely sealing thetube at spaced intervals, while maintaining the inner walls thereof in asterilized condition, to provide a series of integrally connectedhermetically sealed sterile container forming sections which may be cutoff one at a time as desired for use.

It is a more specific object of the invention to form containers byproviding a continuous tube of heat-sealable material. subjecting theinner walls thereof to a sterilizing medium and heat sealing the tubetransversely at predetermined spaced intervals to form a plurality ofintegrally connected hermetically closed and sterile containers or bagswhich may be severed, one at a time, to provide individual open-endedbags when desired.

Itis a still more specific object of the invention to form a continuous,transparent, exible, heat-sealable tube of material while simultaneouslysubjecting the inner walls thereof to a sterilizing treatment andthereafter to transversely seal the tube at predetermined spacedintervals while maintaining the inner Walls thereof in sterile conditionwhereby a plurality of integrally connected hermetically sealed andsterile containers are provided which can be severed between theindividual seals to obtain containers for use as nursing bottles or forenclosing commodities which are intended to be kept substantially freeof bacterial, fungicidal and other contamination.

These and other objects of the invention will be apparent from aVdescription of the preferred form of the container and the method 4ofmaking the same which are illustrated by way of example in theaccompanying drawing, wherein:

2,773,285 Patented Dec. 11, 1956 Fig. 1 is a plan view of a plurality ofintegrally connected containers which embody the principles of theinvention;

Fig. 2 is a perspective View of a roll of the connected containers; and

Fig. 3 is a schematic view illustrating a method of continuously formingthe integrally connected hermetically sealed and sterile containers.

This application is a continuation-impart of our application Serial No.715,940, Sterilized Tubular Container Construction, led December 13,1946, now abandoned.

Referring to Fig. 1 of the drawing, there is illustrated the end portionof a continuous tube of material which has been flattened and dividedinto a plurality of containers 10 by spaced transverse sealing areas orlines by one, by cutting along the dotted lines 12 when they are desiredfor use.

The inner walls of the containers 10 are initially sterilized andmaintained in sterilized condition while the T1. transverse seals aremade so that the inside walls of the In the copending applications ofThomas E. Piazze,

containers 10 are in sterilized condition when furnished to the user andare never exposed to outside air until the individual containers aredetached for use.

The containers are preferably formed of a flexible f transparentmaterial such as polyethylene, rubber hydrochloride, heat-scalablecellophane or equivalent materials. The containers may be made any`desired size such as 4, 6, or 8 ounces as required for nursing bottleuse and they may be conveniently supplied in roll form as illustrated inFig. 2.

In Fig. 3 of the drawing there is diagrammatically illustrated apreferred method of forming a plurality of connected containers whichare sterile on the inside walls and which may be maintained in a sterilecondition until individual containers are detached for use. In carryingout the method a plastic material, preferably polyethylene, is suppliedto an extrusionhead 13 which terminates in a tube forming die 14 havinginternal passageways 15 leading to a forming slot 16 in the lower faceof the die. The plastic material is in the proper condition forextruding from the forming slot 16 in the form of a tube. The extrudedplastic passes into a cooling vessel or container 17, which containswater `or other suitable cooling liquid 18, and is drawn away from theforming die 14 by a pair of rollers 19. The rollers 19 rotate at agreater rate of speed than the travel of the material from the extrusiondie and stretch the material before it sets to reduce the thickness ofthe walls of the tube to the desired dimension.

In order to prevent the plastic tube from collapsing and the inner wallsof the same from Corning together and adhering before the plastic sets,air or other gas is supplied to the inside of the tube as it is beingformed. The air, which may be supplied by means of a pump 20, ispreferably passed through a filter 21 to remove any dirt or solidimpurities. The air is then passed through a coil 22 which is heated byan electric heating element 23 or other heat source and the temperatureis raised to approximately 350 to 400 F. which is above thesterilization point. The heated air is then passed through the formingdie 14 by means of the tube 24, which may have its end projectingslightly beyond the lower face of the die, and into the plastic tube asthe latter is being formed. The heated air prevents the Walls of thetube from collapsing and also sterilizes the inner walls as they arebeing formed.

The formed and sterilized tube is set when it reaches rolls 19 whichflatten the tube and prevent the passage of the internal air used in theforming and sterilizing operation. The tube passes upwardly out of thecooling vessel 17 to a pair of rolls 25 which further atten and creasethe tube. The flattened tube then passes between a pair of rollers 26which are provided with sealing elements 27 which heat-seal the tubetransversely at spaced intervals. The spacing of the transverse sealsmay, of course, be varied to provide containers of any desired capacity.The tube which is now completely formed into a series of integrallyconnected container forming sections may then pass to a wind-up roll 28.Cut-oil? knives 29 may be provided adjacent the transverse seal-formingrolls 26 to permit severance of the Vtube when the roll 28 contains thedesired number `of container forming scctions.

The containers and the method of forming the same which have beenspecificallyV described herewith are merely illustrative of theinvention. The containers may also be formed from one or more webs ofsuitable sheet material by longitudinally sealing the webs into tubeform and providing for sterilization of the inner surfaces of the tubeprior to the forming of the transverse seals.

The sealed and sterile containers which are contemplated by thisinvention are useful not only as disposable nursing bottles but also forthe packaging of commodities which are intended to be kept substantiallyfree of bacterial, fungicidal and other contamination and for many otherpurposes, where it is desired to supply the user with a sterilecontainer which may be easily maintained in sterile condition untilimmediately prior to its actual use.

While specific materials and details of construction have been referredto in describing the preferred form of the container and the method ofmaking the same, it will be understood that other materials and rdetailsof construction may be resorted to within the spirit of the invention.

We claim:

1. A continuous process of forming sterile containers comprisingextruding a thermoplastic material in the form of a hollow tubular body,supplying a fluid medium within the tubular body which is heated to atemperature sulicient for sterilization, maintaining the interior of thetubular body in sterile condition, flattening the tubular body andthereby removing the uid medium from the tubular body, and transverselysealing the tubular body at spaced intervals while maintaining theinterior thereof in sterile condition to provide a plurality ofintegrally connected containers Which are adapted to remain free frominternal contamination until they are individually severed.

2. The process of forming a plurality of integrally connected sterilecontainers comprising extruding a thermoplastic material in the form ofa tube, supplying the interior yof the tube with a fluid medium undersuicient pressure to prevent collapse of the walls of the tube as it isformed, said fluid medium being passed through a lter to removeimpurities and being preheated to a temperature suicient forsterilization, collapsing the walls of the tube to free the same of theuid medium and transversely sealing the tube at longitudinally spacedintervals while maintaining the inner walls thereof in sterilizedcondition thereby providing an integrally connected series ofhermetically sealed containers which may be maintained inV sterilecondition until they are individually severed from each other for use.

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